Fluidic valve-positioning drives are known in various designs and are in service. In this regard, examples such as DE 19537493 C1, EP 1751640 B1, EP 918939 B1, DE 102009023706 A1, EP 1758007, GB 2485049 A, EP 822344 A2 and DE 19502212 C1 can be cited.
As can he inferred in detail from the various prior art documents cited in the foregoing, fluidic positioning drives having a proportional position regulator are typically decidedly complex. This is disadvantageous not only as regards the manufacturing costs. A complex fluidic interconnection of the individual components of the positioning drive additionally conceals the danger of some instabilities of the system.
DE 102007058518 A1 discloses a pneumatic valve-positioning drive that also comprises a drive element to which compressed air can be admitted and a proportional position regulator that regulates the admission of compressed air to the drive element, but compared with the prior art explained hereinabove (e.g. DE 102009023706 A1) is characterized in that the electrofluidic pilot stage comprises precisely one electromechanical transducer (piezoelectric bending transducer) and precisely one proportional valve (nozzle/baffle-plate system) actuated thereby. The control-pressure inlets of the two valves of the power stage are in communication with the output of the proportional valve via corresponding control-pressure lines.
The object of the present invention is to create remedies for the disadvantages of the prior art explained hereinabove, especially by providing a fluidic positioning drive of the type mentioned in the introduction, characterized by a reliable function and high operating safety in combination with relatively low complexity, while at the same time achieving higher efficiency than in the fluidic positioning drive according to DE 102007058518 A1.